Modifying Particle Types

Since many Emitter controls are scaling factors for particle type controls, you need to change the properties of a particle type to change specific particles. (Emitter controls change all particle types at the same time.)

To become comfortable with all the particle type properties, you should play with them and observe changes to the result.

Note: The order the particle types appear in the hierarchy (in Timeline or Workspace panel) is not important and cannot be changed.

You can turn off a particle type (temporarily) by clicking the asterisk icon next to it in the Workspace panel. If you are not going to use it, you can delete it. If the particle type uses a multi-frame shape, you should consider deleting it to save memory.

In the Timeline, you can animate many of the controls for a particle type.

To modify a particle type:

1. Select the particle type in the Workspace panel.



The Particles preview shows only the particle type. Many of the changes you make to a particle type can be immediately seen in the preview.

Note: If you see all particle types for the emitter, enable the Show Particle Types option in the Preview menu.

2. Click Particles to access the Particles controls.

For information on reference points, see Changing the Particle Reference Point. For other controls, see Particles Controls.

3. If the particle type uses a multi-frame shape, you can scrub the thumbnail to see all the images.

The controls for multi-frame shapes are explained in Random Start Frame, Start At, and Hold.

4. Click Behavior to access the Behavior controls.

For information on specific properties, see Behavior Controls.

5. Use the Behavior controls (or the Timeline) to change the basic and variation properties.

Note: The over-life properties should only be changed in the Timeline in Graph view.

6. Click Shape to access the Shape controls.

For information on shape controls, see Shape Controls. To learn how to use a different shape, see Working with Particle Shapes.

7. To see the shape for the selected particle type, click Current.

Changing the Particle Reference Point

Each particle shape has a reference point, which is the point to which its behavior transforms (the three sets of Spin and Size behavior properties) are referenced.

For example, the reference point is important when the particle is spinning since rotation occurs about the reference point. You can also change the reference point for particles types with Single Particle enabled to make it easier to place the emitter in the scene, or to make it rotate correctly.

Each particle has a local axis. If you think of a clock face, the local axis for the particle is the center. The reference point for the particle type is used to position the particle on the clock face. By default, the reference point for a particle type is set at the center of the shape image, so the particle appears at the center of the clock face.

As you move the reference point away from the center of the shape image, the particle (on the clock face) moves away from the local axis (the center of the clock). In other words, the reference point stays at the center of the clock—when the particle spins, it will spin around the clock. The tip of the clock hand is where the particle is.

You change the reference point to define the distance and angle. To continue with the clock analogy, the length of the hand is the distance, and the angle from the center of the shape image to the reference point controls the orientation of the shape at the end of the clock hand.

The particles for a particle type emit from emission points. For a point emitter, there is only one such point; for line, circle, and area emitters, there can be any number of such points. In the following example, the line emitter has two emission points.

In the following image, the reference point has been moved to the left of the shape image (180 degrees from where it was initially). In turn, the orientation of the particles changes.

Note: You can quickly switch the reference point 180 degrees by enabling Flip X.

As a particle spins around its reference point, the local axis for the particle moves according to weight, velocity, and other properties.

In the following image, the weight has been decreased, so the particles drift upward. Each particle continues to spin around its local axis, but the weight affects the drifting motion of that axis.

Initially, the local axis for a particle type is at the same position as the emission point. The particle's local axis only stays at the emission point if the particle type has no weight or velocity and the emitter is stationary, or if Single Particle is enabled. In the latter case, the particle's local axis is attached to the emission point.

Note: For line emitters, changing pivot point affects the reference point and vice versa. (For other types of emitter, you cannot set pivot point.)

To move the reference point:

1. Click Particles to show the Particles controls.
2. Enable the Ref. Point button.

The reference point is shown on the thumbnail with a red dot.

3. To move the point, click or drag in the thumbnail.

You can set the reference point anywhere; it does not need to be on the shape image. For example, you can click on the shape and then drag away from the shape if you want.

4. As you work with the reference point, do any of the following:
• To undo a position change, choose Edit | Undo.
• To place the reference point in the center of the image, right-click (Windows) or Ctrl-click (Macintosh) the thumbnail and choose Center Ref. Point.
• To zoom the thumbnail, Ctrl-drag (Windows) or Command-drag (Macintosh) left and right.
• To pan the thumbnail, Alt-drag (Windows) or Option-drag (Macintosh).
• To reset the zoom level, right-click (Windows) or Ctrl-click (Macintosh) the thumbnail, and choose Fit in Window.
• To show the transparency of the shape image using a checkerboard pattern, right-click (Windows) or Ctrl-click (Macintosh) the thumbnail and enable Show Transparency.

Note: Usually, it is easier to see the shape against a solid black background (Show Transparency disabled).

5. When you are finished, disable Ref. Point. The image is zoomed to fit in the thumbnail.

Note: The reference point is saved with the particle type, not with the shape image. Thus, changing the reference point does not affect the particle types of other emitters that use the same shape.

Changing Particle Colors

Several variables contribute to the color of particles:

• The colors of the shape image (if the color depth of the shape is Color).
• The Life Color for the instant in a particle's life.
• The tint color and strength for the emitter (that is, the one tint for all the particle types coming from the emitter properties).
• The way the colors are combined (for example, the additive mode for Intense particle types) and the way the particles are moving (that is, if they are on top of each other or drifting away).

Changing Particle Transparency

Several variables contribute to the transparency of particles:

• The alpha channel of the shape image (or pixel value is shape has Gray color depth).
• The Life Opacity for the instant in a particle's life.
• The Visibility property for the particle type.
• The Visibility scaling factor for the emitter.

For example, if you want to have completely opaque particles (for sprite animation, for example), you cannot use the Gray color depth.